About group B streptococcal infections

Group B Streptococcus (GBS) are bacteria related to (but not the same as) the group A streptococcus (sore throat or flesh-eating bug) which look like small round beads under the microscope and which produce a range of toxins and surface proteins which combat the human immune system and also cause disease. Group B streps (GBS) have been studied extensively because they can cause serious disease in newborn babies; much less is known about disease in adults. The group B strep is also known as Streptococcus agalactiae.

Group B strep normally live in people’s intestinal tracts and genital tracts without causing any problem; this may be commoner in pregnancy and anyway may vary from week to week. It is believed that babies become coated (‘colonised’) with the bug at the time of birth, as they pass through the birth canal (either from bugs in the intestinal tract or the vagina). Some women may be more at risk of being colonised than others, and doctors are trying to work out a way of identifying those who might benefit from antibiotics to clear colonisation just in time for delivery. Babies can also pick up the bug after delivery, usually from their mother or main carer Very occasionally, the bug can be transmitted from baby to baby via carers in a nursery setting.